1. Field of the Invention
This invention relates generally to cutting devices that perform specialized functions; and more particularly an automated or semiautomated apparatus which cuts the ends of preassembled venetian blinds to provide custom-size blinds. The invention is also directed to a method for cutting such preassembled venetian blinds.
2. Prior Art
A venetian blind is a well-known window covering that can be placed in a window to regulate the passage of sun or air A venetian blind is generally made with a "top rail" or "head rail," a "bottom rail," and a number of thin, very generally planar slats of wood, metal or plastic that are uniformly spaced between the top and bottom rails.
The "top rail" is usually an elongated, U-shaped channel that is attached above or even with the top of the window casing. The "bottom rail" is usually an elongated bar made from wood, metal or plastic. The top rail includes or is operatively connected with a tilt mechanism, for purposes explained below.
The slats are usually supported by ladder tapes, one located near each end of the array of slats and rails. The ladder tapes are attached to the tilt mechanism or to the top rail and extend down to the bottom rail. Each ladder tape is generally made up of two mutually parallel vertical cords or strips--one in front of the slats and one behind them--connected to each other by a series of short cross-pieces of cord. Each cross-piece serves as a support for one end of one slat.
The tilt mechanism located in or connected with the top rail can be operated--typically by a control cord hanging near a first end of the rail. The tilt mechanism skews the ladder tapes and thereby tilts the slats through a wide range of angular positions.
A pull cord is typically affixed to the bottom rail, for use in lifting that rail to gather the slats and bottom rail together at the top. The cord passes through holes in the slats to a series of pulleys in the top rail, and hangs from a final pulley near a second end of the top rail.
At present, high-volume production machinery is used to manufacture venetian blinds in large quantities for modern standard window sizes. Unfortunately these blinds do not fit the windows in many old buildings, constructed to different standards.
Venetian blind manufacturers generally refrain from making blinds for such windows. The demand for such blinds--and consequently the efficiency and the return on investment in producing them--are very low relative to production-line work on modern standard sizes.
A person requiring a venetian blind for an "odd size" window usually finds a manufacturer willing to accept a special order for a custom-cut blind. Such a manufacturer, however, usually incurs large additional costs which he must pass on to the customer.
One alternative for a person needing an odd-size blind for a window in an old building is to contact antique or used-furniture stores to purchase an old, used blind that was specifically manufactured to fit the particular size of the window. As will be evident, however, success of such a search is hardly guaranteed. Furthermore, if such a blind is located it is an old, rather than a new venetian blind.
A person can purchase a new standard-size blind and live with the fact that it is larger or smaller than the window. As a last resort, such a standard blind might be hand-cut to size--but as far as I know that is unheard of On a commercial basis it is uneconomic, and on a do-it-yourself basis for most people it is tedious and nearly unfeasible. Special equipment is needed to cut slats neatly with proper shaping of the corners.
All these alternatives are plainly unsatisfactory. A venetian blind is an excellent window covering, but there is a need to facilitate preparation of custom-size blinds.